81865204 has 6 divisors (see below), whose sum is σ = 143264114. Its totient is φ = 40932600.

The previous prime is 81865181. The next prime is 81865207. The reversal of 81865204 is 40256818.

It can be written as a sum of positive squares in only one way, i.e., 67272804 + 14592400 = 8202^2 + 3820^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81865204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81865207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10233147 + ... + 10233154.

Almost surely, 2^81865204 is an apocalyptic number.

It is an amenable number.

81865204 is a deficient number, since it is larger than the sum of its proper divisors (61398910).

81865204 is a wasteful number, since it uses less digits than its factorization.

81865204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20466305 (or 20466303 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 34.

The square root of 81865204 is about 9047.9392128816. The cubic root of 81865204 is about 434.2099616215.

The spelling of 81865204 in words is "eighty-one million, eight hundred sixty-five thousand, two hundred four".